Propeller



Get. 6,1925. 1,556,012

' A. FLETTNER PROPELLER FiledFeb; 2a, 1922 4 SheetsSheet 1 Hg] P igtZ. Tigi.

f e 9 9 72 y 1720672502" Anion Fleiiner 1,556,012. A. FLETTNER PROPELLER Filed Feb. 23. 1922 4 Sheets-Sheet 2 17222672 for Anian FZeZin by I F.

A! ttorney.

Oct. 6, 1925.

A. FLETTNER PROPELLER Filed Feb; 28, 1922 4,5heets-Sheet 4 r g n k wr n [m y b Patented Oct. 6, 1925.

PATIENT oFFica.

"UNITED srarss Application fled retrai as, 1m. semi in. 540,000.

To all whom it may concern: Be it known that I, ANTON Fnnrrnan, a

citizen of Germany, residing at Berlin,

German have invented certain new and useful which I have filed an application in Germany on March 9, 1921), of which the following is a specification.

My invention relates to the vanes or blades of screws, propellers, turbines, fan rotors, wind wheels, sails of wind mills and the like. It is an object of my invention to increase with the least possible expenditure of po yer the efiiciency of such devices.

As is well known to those skilled in the art, in order to obtain maximum efliciency,

in screws or propellers for driving-water craft, air craft or other vehicles or in screws serving to convert streaming energy into a rotary energy, as, in power engines, or rotary energy into streaming energy, as in I working machines, it is desirable to vary the angular position of the blades or vanes of the screw or prdpeller so as to adapt it to the conditions prevailing in each individual case, no matter whether and towhat extent the direction of rotation or motion or the travellin velocity of the vehi le or the movin in ium may vary. Suc propellers as have hitherto been provided with adjustable blades are so designed, that\the blades are rotatably arrang and as a rule have to be ad usted by means of a gearing extending through the hollow shaft of the propeller. This gearing has to take up the power transmitted in the form of a turning moment from the blade onto the shaft or vice versa. On the other hand it must be strong enough to resist the strains exerted by the streaming medium on the point where the blade is fixed to the hub. These mechanical, conditions render the design of movable blades com licated.

On the other hand a great *exp'en iture of power is required for adjusting the blades,

when the propeller is running.

It has already been proposed to employ propeller blades capable of turning freely and which will adjust themselves automatically under the influence of the current, so as to assume the most effective position. This result has been obtained either by giving the blades a suitable form or by causing the centrifu al forceto act on the blades, so as to a just them against the action mprovements in Propellers (for.

ed in the hub of springs. 'It has further been roposed to supply the adjustable blades 0 lifting screws with a t:jgid covering surface or with surfaces .PIVO to the shaft of the screw and servin for adjusting the screw blades. However, a 1 these arrangements are urely automatic, the blades being only capa le of assuming certain positions without being able to provide for emergencies resulting from altered conditions of flow or drive. Furthermore, an these arran ements involve the drawback that they 0 not allow of belng operated by the attendant. In

consequence thereof, none of these arrangements have been put to practical use.

It is an objectvof my invention to render the blades of screws, propellers or other rotors of this kind adjustable during working, while at the same time keeping extremely small the expenditure of power,

lade in order to adust it and also the strains exerted on the lade by the medium wherein it is working.

My invention relates to arrangements of adjustable blades for rotors of the type dofined, in which the current pressure acting on the blade is utilized for adjusting the blade. To this end I arrange, according to my invention, on the blade either at the entrance rim or at the discharge rim or else at some distance from these rims, a governing surface capable of moving relatively to the blade and together with the blade. In-the majority of cases I have found it useful to arrange such governing surface near the discharge rim or at some distance therefrom, although it may in some cases be arranged with advantage at or near the opposite rim. If the governing surface is dlsposed at an angle to the blade surface, then no matter what position the blade assumes on the hub, the current flowing along the blade will exert on opposite sides of the blade different pressures differing from one another, which will turn the blade until it has adjusted itself in a posltion of equilibrium corresponding to the direction of rotation and to the number of revolutions of the screw in each individual case.

The governing surface can either adjust required to act on the the blade automatically so that it assumes vane as required by the direction of rotaa rack an being tion and the velocity of the rotor. In either case the end positions of the blade or vane may be determined by stops or else the pressure of flow may be utilized for holding the blade or vane in the operative position required in each individual case.

By suitably choosing the-size and configuration, cross section or angular, position of the governing surface the blade or vane can be brought to adjust itself to the most favorable pitch for each variation of velocity which ma arise during operation. By making varia le any one of the said data, it is possible to vary the pitch of the screw in accordance with any desired rule of variation within the whole range of velocities for instance so as to increase or reduce the pitch uniformly or non-uniformly as the velocity increases, or in any othersuitable maimer.

In the drawings affixed to this specification and forming part thereof.

Figs. 1 to 7 are diagrams serving to illustrate in a general way the different means for carrying out my invention and the different ways in which they'act, while Fi s. 8 to 22 disclose several modifications of a s ip propeller embodying my invention.

In the drawings-- Figs. 1 to 7 illustrate a rotor having a blade movably arran ed thereon and a governing surface movab y connected with such blade, the blade and the governing surface shown in seven different positions accordmg to the direction of rotatlon, of travel and of current, respectively.

Fig. 8 is an elevation, part1 in section, of part of a propeller whose bla es are provided with movable governing surfaces,

Figs. 9 and 10 are sections on line III F III and IVIV in Fig. 8, respectively,

Fig. 11 is an elevation, partly in section of a propeller whose governing surface 00- operates with a toothed sector and pinion,

Fig. 12 is an elevation, partly in section, of a propeller whose governing surfaces are connected by aid of a rope drive with a direction. governor,

Fig. 13 is a section on line VII-VII in Fig. 12,

ig. 14 is an elevation, partly isometric and partly in' section, of a propeller whose governing surfaces are connected with the irection (governor through the medium of pinion,

Fig. 15 is a section on line IX--IX in Fi Fig. 16 is an elevation, partly in section at right angles to the axis of the propeller shaft, and

Fig. 17 is an elevation, partly in section in theaxis of the propeller shaft, of a propeller in which the governing surfaces are connected with the direction governor" by a rope drive, the entire operating gear being concealed in the hollow boss of the propeller.

Figs. 18 to 20 illustrate various positions of a blade and governing surface of the propeller illustrated in Figs. 16 and 17.

Fig. 21 is an elevation, artly in section, of a propeller in which the rope drive is partly inserted in a tube ri idly connecting the blade with the frame 0 the rope pulley gear, and f Fig. 22 is an elevation, partly in section, of a blade provided with two governing surfaces- Figures 1 to 4 disclose in a diagrammatic manner the rotor of a machine, which may be a propeller, or a screw, a turbine, a screw pump, a compressor or a wing wheel, a centrifugal pump, or some other machine which serves for converting the energy of a flowing medium into rotary energy, or rotary ener y into propulsive motion of a vehicle or of t e medium in which the rotor moves.

Referring first to F i 1, e is a propeller shaft and f is the blati movably arranged on its pin g. At the end of the blade the governing surface It is arranged to be adjusted about a pin '5 fixed to the blade. If now the governing surface is turned from the position of zero shown in Fig. 1, in one sense or the other (Figs. 2 and 3) and the shaft caused to rotate in the direction of the arrow, then the pressure exerted on the blade by the current will cause the blade to adjust itself in one or the other sense as disclosed in Figs. 4 and 5, respectively, which show that with the shaft permanently turning in one and the same direction the direction of travel which is indicated by the straight arrows can be changed in one or the other sense. With this arrangement it is possible for instance to reverse the direction of travel of the ship without changing the direction of rotation of the engines or of the shaft.

According to the angular adjustment of these small governing surfaces, the blades can be imparted the most advantageous an ular positlon for each travelling speed. T e conditions illustrated by Figs. 1 to 5 prevail as well in the case of propellers as of screw pumps. By suitably adjusting the governmg surface the blade can be imparted the most favourable itch for the number of ro-.

tations required 1n each case and by adjusting the blade to either side of a zero position at right angles to the shaft a change in, the direction of travel or conveying can be verted into rotating ener obtained in one or the other sense without changing the direction of rotatrom Blades controlled by governlng surfaces are useful not only in those cases where the face in such manner, that wit out changing the direction of the current the shaft will turn in one or the other sense.

In the exampleillustrated in Figs. 6 and 7 the blade'is swung about a osition of zero longitudinally of the shaft 1n order to re-' be turned in one or the other sense, rela-- tively to the blade assuming its position of zero, the blade is held by t e current pressure in one or the other osition and the screw will turn in one or t e other sense, as shown by the curved arrows. Ifthe blade is free to turn in a full circle and the means for adjusting the governing surface are so desi ed that this surface will .not hinder the lade to turn round, the arrangement may be made such, that on the direction of the current being reversed, the blade as well as the governing-surface will turn from the unstable osition shown in Figs. 6 and 7 through a out 180 into) the stable position and will adjust themselves in this new sition in the most favourable angular posltion according to the velocity prevailing in each individual case.

Similar conditions prevail in'the case of the propeller illustrated in Figs. 1 to 5. In this case as well it is possible to cause the system, as the direction of rotation is reversed to adjust itself automatically into the new position. In all arrangements the gear ing between the driving means for the governing surface and the blades (which may consist for instance of crossed rope drives or the like) are preferably designed in such manner that as-the blade is adjusted by the governing surface, this latter is automati cally carried back into the position of zero and is thus rendered operat1ve as shown in Fi s. 4 and 5 as compared with Fi s. 2 and 3. n the propeller illustrated in %igs. 8 to 10 the blades 11 are free to turn about spokes 12 extending from bases 13 formed on the hollow boss 14. The governing surface 17 is hinged on pins 18 extending in arallel with the axis,of rotation of the lade and arranged in a recess 15 formed in the discharge rim 16 of the blade. An arm 19 is secured to the hinge pin 18,

which is nearest to the boss 14, and connected with a crank arm 21- by a link 20. The crank arm is secured to a shaft 22 which extends through the hollow spoke 12 into the hollow boss 14. The arrangement of parts is such that the overning surface 17 stands at an angle to t e blade 11 when this latter is in its zero position, that is, at right angles to the ropeller shaft, so 'that the governing sur ace is capable of turning the blade into 0 erative position when the propeller shaft gins to rotate. Astop block 23 is secured to the lower end of the spindle 12, which, when the blade is turned 180?, forces the pawls 25, ressed against it by s rings 24, back so far t at the governing sur ace 17 is free to turn through a predetermined angle when a one-sided pressure is exerted on it. The arm 19 and the crank 21 extend in opposite directions, as shown in Fi 9.

When the direction of rotation of the propeller is reversed so that the discharge rim acts as the vane edge, the blade, which is now in a osition of instability, is turned 180 de rees y the current into the position of sta ility and owing to the governing surface 17 being again correctly adjusted in consequence .of the arrangement of its gear is held in the correct angular osition. In this new position the block 23 is again held in its position of rest by the pawls 25.

If an automatic adjustment of the main surface by means of the governing surface shall be obtained within a smaller angle, for instance in order to maintain the main surface in a preferred working osition, an arrangement, such as shown in ig. 11, can

be used. The blade 31 is free to turn about the spoke 32 and is prevented from slipping ofi b a nut 33 on the end of the spoke. A. toothe segment 35 keyed onto an axial extension 34 of the spoke 32 meshes with a gear 37 located on pins 36 in a recess of the blade 31 and connected with agoverning surface 39 by means of a crank gear 38 similar to the one described with reference to Figs. 8 and 9. The governing surface 39 is pivoted in a recess of the blade at the discharge rim 40.

When the propeller rotates in the direction of the arrow, the pressure of the current acts on the governing surface and places it in the correct angular position in relation to the blade 31 which is thereby adjusted also in the correct angular position. While the blade 31 is bem turned into this position, the gear wheel 3 is compelled by the crank gear 38 to roll on the segment 35, thereby causin a backward rotation of the governing sur ace 39. As soon, however, as a variation in thecurrent tends to move the blade 31 out ofits position of maximum efficiency, the governing surface 39 owing to the connection existing between the spoke. 32 and the governing surface, is displaced angular-1y with regard to the blade, whereby a difference of pressure is again produced which causes the blade to return into its position of maximum efliciency.

As long as the propeller shall work only in one direction and it is only desired to automatically maintain the most favorable angular position within narrow angular limits this can be obtained b means of the segment 35 fixed to the spolie 32 which serves as direction governor and, consequently, forces the blade within given limits to assume a predetermined position which is determined by the conditions of Working prevailing in each individual case.

If this direction governor be so designed as to be capable of assuming two diametrically opposite positions, the blade can be adjusted by aid of the direction governor, for both directions of rotation, in other words, it can be reversed. The reversin of the direction governor itself might be effiected in a case of particular simplicity by manual engagement right at the place where it is'secured to the blade, for instance by turning the block 23 (Fig. 8) together with the gearing 21, 20, blade 11 and governing surface 17 180 by hand, or by lifting the toothed segment 35 (Fig. 11 free of the spoke 32, turning, it 180 by and together with the gearing 37 38 and blades 31 and 39 and refastening it on the spoke for instance by means of the nut 33. As a rule however the reversing of the direction gov: ernor will be effected in the cat majority of cases by suitable mechanlsm extending through the hollow propeller shaft.

In the devices above described the propeller shaft is reversed'in order to reverse the ship, and the blades are turned accordingl y through an angle of 180 degrees. The course of the ship may however, also be reversed by keeping the shaft rotating in the same direction and merely altering the position of the blades in relation to the shaft. In this latter case, the blade need merely be turned through an angle of about 45 degrees to one or the other side from its zero position in which its surface extends at right angles to the shaft.

Figs. 12 and 13 illustrate a simple device of this kind. A shaft 43 extends through the spoke 40 on the hollow boss 41 on which the blade 42 is free to turn. A

bevel gear 44 is secured to the inner end of the shaft 43 and a rope pulley 45 to the outer end, this pulley being connected by a crossed rope 46 with a pulley 47 arranged on a pivot of the governing surface 48. By means of a large bevel gear 49 (the direction governor) which is keyed onto a spindle 49" Within the hollow boss 41 (the spindle being for instance controlled from and the rope pulleys 45 of all the blades are turned simultaneously and through equal angles.

By turning the direction governor out of its zero position to one side soadjusts the governingsurface that at a given direction of rotation of the propeller shaft the governing surface will cause the blade to move into the correct angular position corresponding to the veloei'typrevailing at the time in one direction of travel, whereas by turning the direction governor from its zero position in opposite direction, with the propeller shaft rotating in the same direction as before, the governing surface will cause the blade to move into the position of maximum efficiency which corresponds to the velocity prevailing at the time in the opposite direction of travel.

If the governing surface is placed under pressure, its efliciency can be increased by inserting between the cog wheel 49 serving as direction governor and the governing surface a step-up gearing. In accordance therewith, the diameter of sheave 45 has been chosen considerably larger than that of sheave 47. This arrangement has the effect that already small deflections of the main surface 42, no matter whether they have been brought about urposely or whether they are merely acci ental and are caused by disturbing influences of the flow, will result in a quick return or corrective movement of the governing surface 48.

In this device as well the governing surface is independent from the direction governor inasmuch as it automatically counteracts deviations of the blade from its correct position such deviations occurring for instance in consequence of temporary variations of the'current, the governing surface being bodily rotated with the blade about the shaft 43 and being turned in opposite direction by the crossed rope, as it unwinds from the stationar pulley 45, so that the governing surface 1s carried into an angular position relatively to the blade whereby a difference of pressure is created between the front and the rear faces of the governing surface. This difference of pressure is balanced again by the turning back of the blade. This shows that the stationary direcpeller shaftcontinues rotating in the same direction. v

In Figs. 14 and 15 there is. illustrated another device for reversing the direction of travel without reversing the propeller shaft. Here the rope shown in Figs. 12 and 13 is replaced by a crank gear and the step-up gearing is arranged within the boss. The spindle 50 of the crank gear 51, which acts on the governing surface 52, extends through a hollow spindle 53 inserted in the boss 54 and the spoke 55 and provided at its inner end with a U-shaped frame 56 carrying a train of gear wheels comprising a large wheel 57- meshing with a rack 58, intermediate wheels 59, 60, 61 and a direction governor wheel 62 on spindle 50. The manner in which the governing surface 52 is ad'usted by means of the rack 58 which may e actuated by way of the hollow ropeller shaft will be readily understood ronr the foregoing.

In the device illustrated in Figs. 16 to 20, the direction governor is connected with the governing surface by means of a rope drive as in the 13. However the entire mechanism is here arranged within the hollow boss and the ropes are guided in a particularly simple manner.

The movable blade 7 0 does not turn about a spoke, but is movably located by means 0 a flanged journal 71 in-a projection 72 of the hollow boss 73. A disc 74 secured to the journal 71 within the boss 73 supports the rope gear comprising six horizontal and two vertical sheaves. The horizontal sheaves 75, 76 are arranged in groups of three in two lanes. Each one of the vertical sheaves 7, 78 leads the rope to one into the blade, around the sheave 81 fixed to a pin of the governing surface 82, then back through the blade and over the vertical sheave 78 and the other group of horizontal sheaves 76 to another disc 83 where its free end is secured to a spring 84. The discs 80, 83 are fixed on a rod 85 ada ted to be moved axially in the hollow boss 3. The rope is guided in intersecting borings of the blade which, are preferably milled into the surface of the blade and then closed by a suitable co'ver after the ropes have been lnserted.

Owing to the sheaves turning bodily with the blade, the rope can unwind therefrom so that, whenever the blade leaves its correct position, the governing surface is displaced automatically and counteracts the movement of the blade. On the other hand, by shifting the rod 85 and the discs 80 and 83 in one or the other direction, a pull is exerted on one device illustrated-in Figs. 12 and gears, gear wheels and r0 or the other end of the rope, whereby the governing surface is caused to be adjusted 1n accordance with the velocity or turned in one or the other direction, as shown in Fig. 10 so as to reverse the blade and the direction of travel.

While the blade is being reversed, the overning surface owing to the rope unwin ing from the sheave 81 will return to its zero position in relation to the blade.

If, as illustrated in Fig. 21, the frame 90 of the ropp gear is rigidly connected with the pivoted lade 92 by a tube 91, thus causing the sheaves to turn with the blade, an automatic governing surface is obtained as in the case of the devices illustrated in Figs. 8 to 11, no automatic reversing action taking lace. In this case, the blade is automat- 1cally turned through about 180 degrees when the direction of rotation of the propeller shaft is reversed, is then adjusted to a position corresponding to the velocity and maintained in this position by the governing surface.

In all the devices illustrated, each blade has been shown as provided with a single governing surface only. I may, however,

rovide several such governing surfaces or each blade acting either in parallel or in series. In Fig. 22, two governing surfaces 100 and 102 are shown arranged in series the f smaller one (100) being adjusted by the direction governor 101 and on being turned through an angle, causir'fg the larger surface 102 to turn also and to assume an an ar position relativel to the blade whic is thereby turned. ny undesired turning motion of the blade will be instantly counteracted by the smaller surface 100 causing the larger one to be deflected and to turnthe blade back, as described above for blades having but a single surface.

The governing surfaces need not be arbut may be connected with the blade by levers. However, the arrangement shown and described is preferable inasmuch as it leaves the surface of the blade smooth. By

making the discharge rim of the blade, or in the case of a plurality of overning surfaces'being provided, of the arger surfaces,

sufficiently wide, the front edge of the governing surface can be prevented from projecting beyond the blade surface when the governing surface isbeing turned.

Instead of the gears illustrated crank drives any other gears, and even hydraullc gearing may be provided.

In the devices illustrated in Figs. 16 to 20 the direction of travel or of conveying is reversed without changing the direction of rotation by turning the governing surface to one or the other side from a zero position at right angles to the shaft. If, on the other ranged in a recess of the blade, as illustrated,

hand, it be desired to alter thedirection of rotation without altering the direction of travel or of conveyin the blade instead of being caused to pass from a zero position at right angles to the shaft into the operative position, may be used to assume a zero posi-' tion in parallel to the shaft.

The angle of deflection of the governing surface may be so chosen that the angular position of the propeller blade is increased or reduced at increasing velocity.

I am thus enabled to alter the direction of travel or of conveyin by simply reversing the direction of rotatlon of the shaft or to reverse the direction of rotation b reversing the direction of the current, or e se to alter the direction of travel or of conveying by adjusting the blade by means of the governing surface without altering the direction of rotation, and to impart to the blade the position of highest efliciency corresponding to the velocity prevailing at each moment.

My invention may be applied to propellers and rotors of any kind, as employed in connection with water or air craft (ships, air

, ships and flying machines) further to fans,

compressors for air or water or any other materials, to conveyors and the like, and also to prime movers such as turbines, wind wheels and wind sails, for instance in wind mills.

I wish it to be understood thatI do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim:

1. A rotorcomprising in combination a blade loosely movable about an axis extending at an angle to the rotor axis and a governing surface movably connected with such blade for adjusting the blade under the action of current pressure.

2. A rotor comprising in combination a blade loosely movable about an axis extending at an angle to the rotor axis and a governing surface pivotally connected with such blade for adjusting the blade under the action of current pressure.

3. A rotor comprising in combination a blade loosely movable about an axis extending transversely to the rotor axis and a governing surface pivotally disposed near the discharge rim of such blade for-adjusting the blade under the action of current pressure.

4. A rotor comprising in combination a blade loosely movable about an axis extending transversely to the rotor axis and a governing surface adjustably connected with such blade for adjusting the blade under the action of current pressure.

5. A rotor comprising in combination a blade loosely movable about an axis extending at an angle to the rotor axis, a governin surface connected with such blade for a justmg the blade under the action of current pressure and means adapted to be actuated at will for adjusting said governing surface relatively to said blade.

6. A rotor comprising in combination a blade loosely movable about an axis extending at an angle to the rotor axis, a governing surface connected withsuch blade for adjusting the blade under the action of current pressure, and means extending in the rotor axis for adjustin said governing surface relatively to said%)lade.

7. A rotor comprisin in combination a blade loosely movable a ut an axis extending at an angle to the rotor axis, a governing surface connected with such blade for adjusting the blade under the action of current pressure and means extending in the rotor and the blade axes for adjustlng said governing surface relatively to said blade.

8. A rotor comprising in combination a blade loosely movable about an axis extending at an angle to the rotor axis, a governing surface movably connected with such blade for adjusting the blade under the action of urrent pressure and a stop for limiting the movement of said surface.

9. A rotor comprising in combination a blade loosely movable about an axis extending at an angle to the rotor axis, a'governing surface movably connected with such blade for adjusting the blade under the action of current pressure and a gear between said blade and said surface.

10. A rotor comprising in combination a blade loosely movable about an axis extending at an angle to the rotor axis, a governing surface movably connected with. such blade for adjusting the blade under the action of currentpressure and a geared transmission mechanism between said blade and said surface.

11; A rotor comprising in combination a blade loosely movable'about an axis extending at an angle to the rotor axis, a govern ing surface movably connected with such blade for adjusting the blade under the action of current pressure and a gear between said blade and said surface, said gear being arranged to move about the axis of said blade. i

12. A rotor comprising in combination a blade loosely movable about an axis extending at an angle to the rotor axis, a governing surface movably connected with such blade foradjusting the blade under the action of current pressure and a direction governor for said blade operatively connected with said surface.

13. A rotor comprising in combination, a rotor shaft, a blade loosely movable about an axis extending at-an angle to the rotor axis, a governing surface movably connected with such blade for adjusting the blade under the action of current pressure and a direction governor for said blade disposed axially to said blade and operatively connected with said surface.

14. it rotor comprising in combination, a rotor shaft, a blade loosely movable about an axis extending at an angle to the rotor axis, a governing surface movably connected with such blade for adjusting the blade under the action of current pressure, a direction governor for said blade fixed relatively to said shaft and operatively connected with said surface and means extending axially through said shaft and said blade for adjusting said surface.

15. A rotor com rising in combination a blade loosely mova 1e about an axis extending at an angle to the rotor axis and a plurality of governing surfaces connected with such blade for adjusting the blade under the action of current pressure.

16. A rotor comprising in combination a blade loosely movable about an axis extending at an angle to the rotor axis and a lurality of governing surfaces dispose in series and connected with such blade for adjusting the blade under the action of current pressure.

17. A rotor com rising in combination a blade loosely movable about an axis extending at an angle to the rotor axis, a governing surface movably connected with such blade for adjusting the blade under the action of current ressure, a direction governor for said b ade operatively connected with said surface and a step-up gearing between said surface and said governor.

18. A rotor com rising in combination a blade loosely mova le about an axis extending at an angle to the rotor axis, a plurality of governlng surfaces disposed in series and connected with such blade for adjusting the blade under the action of current pressure and a direction governor for each governing surface with the exception of the last surface.

19. A rotor com rising in combination a blade loosely mova 1e about an axis extending at an angle to the rotor axis, a plurality movably connected with such blade for adof governing surfaces disposed in series and justing the blade under the action of current pressure and a direction governor for gradually increases said blade operatively connected with said surfaces and a gearing between said direction governor and the last surface which towards said surface.

20. A rotor comprising in combination, a rotor shaft, an arm on said shaft, extending at an angle thereto, a blade loosely movable about said arm and provided with a recess for fixing it on said arm and a governing surface connected with suchblade for adjusting the blade under the action of current pressure.

21. A rotor comprising in combination, a rotor shaft, an arm on said shaft, extending at an angle thereto, a blade loosely movable about said arm, a direction governor for said blade, disposed near the outer end of said arm and a governing surface movably connected with said blade for adjusting said blade under the action of current pressure.

22. A rotor comprisingin combination a blade loosely movable about an axis extending at an angle to the rotor axis and a governing surface pivotally disposed in a recess of said blade for adjusting the blade under the action of current pressure.

23.- A rotor comprising in combination, a blade loosely movable about an axis extending at an angle to the rotor axis, a governing surface movably connected with such blade for adjusting the blade under the action of current pressure and a gear between said blade and said surface, said surface and said gear being arranged in such manner as to be capable of carrying said surface back into zero position whenever said blade is adjusted.

24. A rotor com rising in combination a blade loosely mova le about an axis extending at an angle to the rotor axis, a governing surface movably connected with such blade for adjusting the blade under the action of current pressure and a gear between said blade and said surface, said surface and said car being arranged in such manner as to e capable of automatically causing said surface, whenever said blade is deflected accidentally by the current, to be set at such an angle to said blade as to counteract said deflection.

In testimony whereof I aifix my signature.

ANTON FLETTNER.

fill 

